In a vision-assisting device, such as a monocular, the device is collimated when the output optical axis matches the input optical axis such that the beam of light entering the device is parallel with the beam of light exiting the device. Typical assembly procedures produce a device that is not collimated due to inconsistencies in the mounting of various optical elements within the device. A night vision device normally deviates from a collimated system due to the offset caused by the microchannel plate and twisted fiber optic within the device.
When the device is not collimated, the image produced by the system is slightly out of alignment with the input image. Such slight misalignment is typically not a problem for a monocular. However, a binocular constructed from two uncollimated monoculars results in a user's eyes needing to independently point in different directions. This is a very unnatural condition, and often causes the user to experience eyestrain and headaches.
The F5050 night vision goggle collimates one monocular to the other through the use of a mechanism that includes a single eccentric mechanical housing. The single eccentric housing allows shifting of the optical image to approximate a collimated image. However, the F5050 goggles must be aligned as a system. Neither output optical axis is necessarily aligned with the mechanical axis of the binocular, or the input optical axes. If one of the monoculars is replaced or serviced, then both monoculars again need to be collimated to make the output axes parallel.
It would be beneficial to provide a collimated binocular in which a monocular can be replaced or serviced without having to re-collimate both monoculars in the binocular.